Soldering Aluminum and Copper

Is it possible to solder copper to aluminum? Also any advice on soldering copper, I've had some difficulty with it, I have a propane/oxygen little torch....thanks for the help....Casey


B.J. Severtson's picture

Little torch...

Casey.
Do you mean silver solder ? Your torch is a brand name "little Torch" ? What are you trying to solder that you are having trouble with? Brad


KCLS's picture

it's a smith little torch, I

it's a smith little torch, I am using silver solder to try and solder copper to aluminum...I am also having problems getting my solder to flow onto the copper, I am using a ruby liquid flux paste and I've used a general purpose liquid flux and I am going crazy!!! Something is not working....Are there certain metals that can not be soldered together?


Gene Olson's picture

Harris al-solder works

Harris al-solder works nicely.

Clean, clean, clean.

don't overheat. we are only talking 3-400 degrees for soft solders like those.

Gene Olson
Sculptor
Elk River, MN


KCLS's picture

Thanks Gene

Thanks Gene


B.J. Severtson's picture

That Tm Little torch

Cassie,
That Tm Little Torch is a professional tool. I've had several of them over the years. In the fine jewelry world, It's my personal favorite torch. In my shop I would not be able to solder aluminum to copper. I only do gold soldering or silver soldering. I would join copper to aluminum with a cold construction technique. The reason for this is. I don't want there to be any chance that I could ever have a cross contamination problem of any lead or mystery metal getting into my gold or silver work. While my approach might leave me with a slight headache solving design problems, It avoids the migraine headache of contaminated metal. I own some soft solder, it is with my plumbing kit in the shed out back, it Does not enter my jewelry world, or get near my soldering bench. Copper to copper would be an easy silver solder approach. I only find it necessary to have easy and hard temps of silver solder. I stock it in sheet and wire. I use much more easy than hard. I don't find this approach any more limiting than driving on the right side of the road in this country. I use Batterns flux liquid almost exclusively or Handy Flux paste flux. I also use a predip of alcohol and borax solution more to keep diamonds from gathering up carbon, than anything else. Beyond this then soldering comes down to three factors. Clean, clean, clean. emery paper clean or file clean. don't use steel wool it's dirty. Fit, like the way pages in a note book fit together. and heat control. The smallest tip for your torch is capable of welding the links on the finest chain that can be purchased. The temp of the flame is just as hot as the flame from larger tips. The difference is that the larger tips put out more BTU's. Because of the scale of your copper to copper soldering you might find it necessary to go to one of the larger tips above a #3. When you do that remember that you have a lot of torch..Best of luck. I also through method remove the annoying problem of little bits of solder moving all over the place when the flux is heated. I probe apply the solder. This in a nutshell it the approach that works for me. Definitely not the only approach. May your solder always flow, where you want it to. Brad


KCLS's picture

Brad, Thanks you for all the

Brad,

Thanks you for all the information, this will help...

Casey


Rich Waugh's picture

That's a very fine torch,

That's a very fine torch, but it is still an oxy/fuel torch with a flame temp of around 6000 degrees Fahrenheit, so you have to watch out you don't overheat. For soft soldering, I'd suggest a propane/air torch that will be more forgiving.

Soldering aluminum to aluminum is possible with special solders like Harris oand others make. Copper to copper is fine with anything from lead/tin to tin/silver to silver solder. Aluminum to copper is probably not going to work, as I have a feeling that the flux for the aluminum solder isn't going to be appropriate for the copper. Also, the join will be subject to stress from the difference in coefficients of thermal expansion between the two metals.

As Brad said, I'd suggest cold connections like rivets, threaded fitments or even epoxies for joining copper to aluminum. If you're feeling really adventurous and have hundreds of thousands of dollars to throw at the problem, you can try explosive welding or friction welding. This is how copper is clad to aluminum and stainless steel cookware. That's the only real instance I know of copper aand aluminum being durably joined by thermal or diffusion bonding methods.


KCLS's picture

Thanks for your help and

Thanks for your help and information...I will do a cold connection with the alum/copper...Casey


visitor's picture

COPPER TO ALUMINUM

TRY WWW.SOLDER-IT.COM. THEIR ALUMINUM PASTE SOLDER REQUIRES NO FLUX, MELTS AT LOW TEMP AND WILL JOIN COPPER TO ALUMINUM.


visitor's picture

Copper and Aluminum jewelry

I am new to the jewelry making business. I am considering purchasing a soldering tool. I don't want to spend a lot of money. Can anyone recommend an electric tool that is fairly inexpensive? I will probably be soldering copper to copper for right now. Thanks for any help. Susan